Angiogenesis is the development of new blood vessels from preexisting blood vessels Physiologically, angiogenesis ensures proper development of mature organisms, prepares the womb for egg implantation, and plays a key role in wound healing, fracture repair, and the establishment and maintenance of pregnancy. Angiogenesis is also associated with pathological conditions associated with a number of disease states such as cancer, inflammation, and ocular diseases.
Angiogenesis or “neovascularization” is a multi-step process controlled by the balance of pro- and anti-angiogenic factors. The latter stages of this process involve proliferation and organization of endothelial cells (EC) into tube-like structures. Growth factors such as fibroblast growth factor 2 (FGF2) and vascular endothelial growth factor (VEGF) are thought to be key players in promoting endothelial cell growth and differentiation. The endothelial cell is the pivotal component of the angiogenic process and responds to many cytokines through its cell surface receptors and intracellular signaling mechanisms.
Control of angiogenesis is a complex process involving local release of vascular growth factors, extracellular matrix adhesion molecules, and metabolic factors. Mechanical forces within blood vessels may also play a role. The principal classes of endogenous growth factors implicated in new blood vessel growth are the fibroblast growth factor (FGF) family and vascular endothelial growth factor (VEGF). The mitogen-activated protein kinase (MAPK; ERK1/2) signal transduction cascade is involved both in VEGF gene expression and in control of proliferation of vascular endothelial cells.
Many diseases and undesirable conditions could be prevented or alleviated if it were possible to stop the growth and extension of capillary blood vessels under some conditions, at certain times, or in particular tissues. Angiogenesis-dependent diseases that can be treated by the invention disclosed herein are those conditions/diseases which require or induce vascular growth. On the other hand, promotion of angiogenesis is desirable in situations where vascularization is to be established or extended, such as, but not limited to, stroke, heart disease, ulcers, scleroderma and infertility.
It has been proposed that inhibition of angiogenesis would be a useful therapy for restricting the unregulated growth of blood vessels, for example, in tumor growth. Inhibition of angiogenesis can be achieved by inhibiting endothelial cell response to angiogenic stimuli as suggested by Folkman et al., Cancer Biology 3:89-96 (1992), where examples of endothelial cell response inhibitors such as angiostatic steroids, fungally derived products such as filmagilin, platelet factor 4, thrombospondin, alpha-interferon, vitamin D analogs, and D-penicillamine are described. For additional proposed inhibitors of angiogenesis, see Blood et al., Bioch. Biophys. Acta 1032:89-118 (1990), Moses et al., Science 248:1408-1410 (1990), and U.S. Pat. Nos. 5,092,885, 5,112,946, 5,192,744, and 5,202,352.
Inhibiting an undesired angiogenic processes may provide a therapeutic treatment and/or preventive against inappropriate or undesired angiogenesis. Conversely, promoting an angiogenic process may provide a therapeutic treatment for those diseases states that would benefit from angiogenesis. Aspects of the invention disclosed herein provide amphiphilic compounds, such as polycationic compounds, for their anti-angiogenic properties. The ability to inhibit angiogenesis may provide an effective therapeutic tool for modulating angiogenic diseases and/or conditions.